This invention relates to the field of safety cabs for underground mining equipment.
The underground coal mining's industry is faced with a continuing threat to personal safety, namely, the ever present danger of mine roof and sidewall cave-ins. As a result, the federal government has promulgated a number of rules and regulations governing mine safety equipment and operations. These federal underground mining regulations are not continuously changed to meet the methods of coal extraction which are developed out of necessity to meet the demands of new coal finds, primarily in the western United States regions. For example, the location of 30 foot seams demands more strict regulations than are presently in effect.
The Federal Mine Safety Health Administration now regards standard manufactured cabs for continuous coal miners which are on the market as having definite limitations with respect to safety. New safety criteria for mining under high roofs need to be developed and cabs need to be designed for such mining conditions. As the Mine Safety and Health Administration notes, "a cab may give a false sense of security to an operator who believes it capable of withstanding a massive roof fall."
The structure of presently available cabs for continuous coal miners below ground is deficient in being able to withstanding massive roof or lateral roof falls which can crush the cab and trap the operator inside.
Specifically, present mining conditions require a safety enclosure for cabs which will protect the operator from both vertical and lateral falls. The cab should be designed in such a way that the cab, door, and upright standards are designed with triangular tubular steel which acts as a fulcrum when contact is made by a collapsing roof or rib wall.
The cab door should provide a unique tie-in effect with the cab when in the closed position. This would allow maximum support to the hinges, a feature which is not now available.
The angulation of the front portion of the cab should allow any falling coal or rock to slide off the cab after impact and not permit full, flat surface contact to take place.
The crown of the canopy of the cab should likewise be angled to offer something other than a full, flat surface contact with any falling material.
The upright standards of the cab should provide an offsetting force to lateral blows from sidewall falls to permit the fulcrum effect to come into play and prevent shearing of the standards.
While most present cab canopies are anchored at four points on the continuous miner, greater safety demands at least an additional two frontal anchors to the canopies.
An extended front design pattern would protect a methane detector located within the cab.
The cab should be enclosed on all sides with adequate rolled screen to protect the operator from small coal and rock particles. The cab should also be enclosed in the front with heavy rolled screen to protect the operator from the larger chunks of coal and rock falling on the cab during regular coal extraction procedure.